Sure, a modern drivetrain and brakes would be a necessity on a “LeMond reboot”.
My new wheels have rim brakes - I would have added disc if I could. And the rear wheel/hub has room for an extra cog on the cassette. But I feel that once I wear everything out, I’m going to have to bite the bullet and get a new bike rather than fight against the lack of new equipment that fits old bikes :(
No you won’t. Shimano still makes new 7 speed groups even.